VZ Average is a flexible and minimal framework for rating or tallying anything in EE that you can identify with an ID: a channel entry, a comment, a Matrix row, or anything else. A few possible uses for it include: star ratings, thumbs up/down ratings, flagging comments as offensive, voting on entries, etc.

Tally is a simple plugin which allows you to calculate totals or averages for numeric values in an entries loop. A common use for this would be calculating order totals for the month from your e-commerce orders channel, or adding other financial data spreadsheet-style.